Fetal Central Nervous System and Infectious Diseases

Maternal infectious diseases are frequent complications of pregnancy and can cause negative outcomes. Perinatal infections can cause serious damage to fetal central nervous system (CNS), but ncidence of symptomatic congenital infections at birth is low. Complete and multidisciplinary (obstetric, infectologist, microbiologist, neonatologist/pediatrician, psychologist) evaluation of the pregnant women is crucial to define fetal prognosis. The ultrasound (US) surveillance has an irreplaceable role in identifying serious fetal damage and complications. Complete evaluation of the fetus in selected cases needs to be integrated with invasive prenatal diagnosis, particularly amniocentesis, which has optimal predictive values in excluding vertical transmission, and fetal magnetic resonance imaging (MRI), which can add important anatomical detail when fetal CNS damage is suspected. Congenital infections, furthermore, need to be considered in differential diagnosis of some common abnormal CNS findings at prenatal US. With the present review, we intend to provide an overview of the major perinatal infections and the role of US diagnosis in their assessment to recognize fetal CNS damage. We highlight the most recognizable syndromes due to congenital infections by linking etiopathogenesis with pathology and imaging. In particular, we focus on US diagnostic and prognostic values in relation to other invasive and noninvasive prenatal diagnosis options and summarize up-to-date recommendations on US evaluation of most common findings. Cytomegalovirus (CMV) is the most common cause of congenital infection, while Toxoplasmosis is the most preventable cause of infectious CNS damage; rubella, varicella virus, and herpes viruses, even if rarely, may be responsible for extremely serious fetal damage, while Zika virus is an emerging concern on global scale.